Temporal bones will be acquired from human subjects who have a medical history and test data of otological disease. The specimens will dome from the several morgues of the hospitals serving Harvard Medical School, as well as from the Temporal Bone Bank Program and cooperating otolaryngologists in the USA and several foreign countries. The temporal bones will be prepared for either light microscopy, electron microscopy, or histochemistry and, in some instances, more than one method will be used on the same temporal bones. The pathological changes will be identified and quantified as to severity and spatial distribution, and correlations will be made with the corresponding clinical manifestations. The medical records, pathological descriptions and diagnosis will be stored in a computer to facilitate retrieval of data. When sufficient new knowledge has been generated for any particular disorder, and in- depth study will be performed on the involved temporal bones and a report will be made with emphasis on the clinical significance of the findings. It can be anticipated that these studies will further our knowledge of the pathology and causes of otologic disease and will lead to more effective methods of prevention and treatment.